chore: 将 site.ts 移出版本控制，改为 site.ts.example

备案号等敏感配置不再提交到仓库，Footer 改为从 siteConfig 读取。

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

components/layout/Footer.vue

@@ -6,8 +6,10 @@ import { siteConfig } from '~/config/site'
   <footer class="py-6 text-center text-sm border-t" style="color: var(--color-text-secondary); border-color: var(--color-border);">
     <p>
       &copy; {{ new Date().getFullYear() }} {{ siteConfig.siteName }}
-      &nbsp;·&nbsp;
-      <a href="https://beian.miit.gov.cn/" target="_blank" rel="noopener noreferrer" class="hover:opacity-70" style="border-bottom: 1px solid var(--color-text-secondary); padding-bottom: 1px;">蜀ICP备2026028044号</a>
+      <template v-if="siteConfig.icp">
+        &nbsp;·&nbsp;
+        <a href="https://beian.miit.gov.cn/" target="_blank" rel="noopener noreferrer" class="hover:opacity-70" style="border-bottom: 1px solid var(--color-text-secondary); padding-bottom: 1px;">{{ siteConfig.icp }}</a>
+      </template>
     </p>
   </footer>
 </template>